The present invention relates to articles having pressure-sensitive adhesive surfaces having inorganic particulate coatings for participating in the hydration reaction with hydratable cementitious compositions cast against the coated surfaces and allowed to set.
It is known that waterproofing membranes can be provided as pre-formed, sheet-like structures.
For example, U.S. Pat. Nos. 3,741,856 and 3,900,102 of Hurst, incorporated herein by reference, disclosed waterproofing membranes having a carrier support film, and, contiguous thereto, a membrane of a water-proofing pressure-sensitive adhesive. Membrane products of this type can be applied directly onto pre-existing structures, such as concrete foundations or floors. In Hurst ""856, it was further disclosed that aggregate materials, such as sand or cork, could be deposited in granular or powdered form on the carrier support film to protect the membrane from damage and/or so that it could provide an improved keying surface for other material, such as concrete, that was subsequently applied thereto. See Col. 4, II. 62-73.
In U.S. Pat. No. 4,994,328 of Cogliano and U.S. Pat. No. 5,316,848 of Bartlett et al., both of which are incorporated herein by reference, waterproofing membranes were disclosed for so-called xe2x80x9cblind-sidexe2x80x9d waterproofing. This referred to a process in which the carrier side of the waterproofing membrane was affixed against a concrete molding form, and fresh concrete was cast against the adhesive layer and allowed to cure. In other words, the waterproofing was installed first in a xe2x80x9cbackwardsxe2x80x9d arrangement, and the concrete structure (e.g., foundation, deck, wall, etc.) was installed subsequently by casting it against the outward-facing adhesive side of the waterproofing membrane. In both Cogliano and Bartlett et al., a protective coating was disclosed for protecting the adhesive layer against dirt and damage.
Subsequently, in U.S. Pat. No. 5,496,615 of Bartlett et al., also incorporated herein by reference, it was discovered that a finely divided particulate material could be dusted onto the protective coating, so as to sustain foot traffic on the membrane when it was installed in a horizontal position. At the same time, the finely divided particulate dusted layer permitted fresh concrete to be cast onto the protective coating/adhesive layer to form a fully adhered waterproofing bond with the waterproofing membrane. Bartlett et al. disclosed that the particulates could comprise calcium carbonate, sand, silicate sand, cement, talc, titanium dioxide, carbon black, slate dust, granite dust, and clay.
In U.S. Pat. No. 5,543,188 of Te""eni, incorporated herein by reference, a flexible waterproofing membrane was disclosed having a polymeric sheet with an open surface impregnated with a dry cementitious material defining interconnected internal voids. The dry cementitious material included a water-hardenable cement that was substantially non-hydrated and could be incorporated into the open surface as a slurry or dry powder along with additives such as mineral fillers, silica powder, microsilica, and clay minerals.
The present invention differs from the flexible prior art waterproofing membranes wherein aggregates or filler materials are used as particulate materials to be contained within or coated upon waterproofing adhesive (e.g., Hurst, Cogliano, Bartlett et al.) or cement-binding substrate (e.g., Te""eni).
One of the objectives of the present invention is to employ certain inorganic particulate materials, contained within and/or coated as a discrete separate layer upon a pressure-sensitive adhesive layer or surface, that are operative to react with hydroxide solution from the hydration reaction of concrete or mortar, cast against the particulate-coated adhesive, to form hydration products.
In contrast to prior art use of particulates comprising aggregates or fillers, the present invention employs particles that react with hydratable cementitious compositions such as concrete or mortar and/or that accelerate the hydration reaction of such compositions. The particles may comprise, for example, set accelerators, strength enhancing agents, pozzolans and/or pozzolanic materials.
An exemplary coated article of the invention comprises a body having at least one surface for carrying particles, the surface comprising a pressure-sensitive waterproofing adhesive or elastomer, and the particles being inorganic particles operative to react with hydroxide (e.g., hydroxides of alkali and/or alkaline earth metal hydroxides, also possibly aluminum hydroxide) solution from the hydration reaction of concrete or mortar to form hydration products, the inorganic particles being selected from set accelerators, strength enhancers, and pozzolans or pozzolanic type materials.
Preferred particles comprise (a) aluminum oxide trihydrate; (b) silica dioxide; (c) fly ash; (d) blast furnace slag, (e) silica fume; (f) an alkali or alkaline earth metal nitrite, nitrate, halide, sulfate, hydroxide, carboxylate, silicate, aluminate a mixture thereof. Aluminum oxide trihydrate particles are most preferred.
A preferred article comprises a waterproofing membrane comprising a waterproofing adhesive membrane layer coated with powdered aluminum oxide trihydrate, silica dioxide, or a mixture thereof, the particles being in the range of 25-1000 microns. Exemplary waterproofing adhesive layers are preferably pressure-sensitive adhesives comprising rubber modified bitumen, natural or synthetic rubber, a synthetic elastomeric material, or a mixture thereof. Preferred is styrene ethylene butadiene styrene.
Most preferred embodiments of the invention are sheet-like, pre-formed waterproofing membranes comprising a pressure-sensitive waterproofing adhesive layer comprising at least 15% and more preferably 40% by weight of SEBS and/or acrylic rubbers, the layer having at least two major faces, at least one of which is coated with particles 50-100 microns in size of aluminum oxide trihydrate, silica dioxide, or mixture thereof, the particles being preferably embedded in the adhesive and partially exposed and thus operative to bind with calcium hydroxide or other alkaline solution from a hydratable cementitious composition that is cast against the particle-coated adhesive layer. Preferably, the waterproofing adhesive layer is attached to a carrier film support layer contiguous with the major face of the adhesive layer opposite the particle-coating layer, and/or a reinforcing mesh or nonwoven layer can be attached to or embedded within the pressure-sensitive adhesive layer.
Articles of the invention may comprise pressure-sensitive adhesive or elastomeric materials formed at a construction site by liquid application.
In addition to sheet-like structures such as waterproofing membranes, further exemplary articles of the invention can include articles having body portions having surfaces (such as waterstops, hoses, panels) or even thermoplastic surfaces (such as hoses, sheets) for carrying the above-described particulate material for bonding with fresh cementitious compositions.
Preferred particulate materials are silicious, aluminous or pozzolanic. For example, silicon dioxide, aluminum trioxide hydrate, silica fume, pumice, crushed firebrick, etc. Pozzolanic materials include siliceous or siliceous and aluminous materials which in themselves possess little or no cementitious value but will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds possessing cementitious properties in that they will fuse in the chemical reaction that occurs upon intermixing of Portland cement and water. Such pozzolanic materials include fly ash, silica fume, ground blast furnace slag, and limestone.
The present invention also provides cementitious articles such as walls, foundations, masonry units (e.g., pavers, bricks, blocks, segmental retaining walls, etc.) bonded to the above-discussed particle-coated articles.
Further advantages and benefits of the invention are disclosed hereinafter.